1. Field of the Invention
This invention relates to an air suspension system for a vehicle and more particularly to an air suspension system for a vehicle which is designed to permit one end of the vehicle to be lowered or kneeled. Even more particularly, the air suspension system of this invention permits the exhaust of air from the air springs of the suspension system, while preventing the exhaust of air from the auxiliary air reservoirs of the suspension system.
2. Description of the Related Art
Link Manufacturing, Ltd. (“Link”) of Sioux Center, Iowa, markets an air suspension system under the trademark ULTRARIDE®. In the ULTRARIDE® system of Link Manufacturing, a pair of air springs are utilized to support the rear axle of the vehicle frame. In Link's prior art suspension system, the air may be exhausted from the air springs so that the rearward end of the vehicle frame may be lowered for loading purposes such as is desirable with shuttle buses, ambulances, etc. When the air springs are reenergized, the air compressor (the air source for the suspension system) may be unduly taxed which may potentially decrease its life. Further, in Link's prior art system, it takes some time to bring the vehicle to ride-height again which reduces the “drive away time,” which creates problems in the EMS industry where “drive away time” is critical and the vehicle needs to return to ride-height quickly.